Self Healing of KEMET Impregnated Paper Capacitors
If a conducting particle or a voltage surge punctures the dielectric, an arc occurs at the point of failure melting the surrounding metal and insulating the area of the breakdown. In the metallized paper capacitor, as processed by KEMET, a breakdown caused by a short transient normally results in an improvement of the insulation resistance. KEMET metallized paper capacitors are to be preferred if the capacitor is to be used where uncontrolled transient voltages can occur.

Corona Resistance of KEMET Impregnated Paper Capacitors
KEMET RC Network impregnated capacitors feature a impregnation technique that eliminates pin-holes, thus also eliminating potential gas cells. This elimination of potential gas cells cannot entirely eliminate the possibility of weak points in the winding. These could result in a glow discharge, but the occurrence of such a discharge will eliminate the weak points and improve the insulation resistance thereafter due to a good self-healing process. In addition, laboratory tests and applications reports verify that KEMET RC Network metallized paper capacitors can withstand very high levels of dU/dt, unique to metallized paper capacitors.